HD Formating problem

i have came acrossed a bunch of hard drives in a box that i have been collecting for a while, i want to put them to goo use for like back up stuff. anyways, i bought a extrnal case and i hook them up and connect them to mny computer....and nothing happens. only two out of the five popup up to view files and stuff like that. the funny part is, i 100% sure they all work...what can i do to make them formatable?

no older than like 2 years..all 10-20 gb...also when i was messing around with the xbox moding i used one, and ended up switching to a bigger one, and since its formated to xbox standards i dont know how to format it...

Not sure what the Xbox uses specifically... If you're sure they're compatible, check the partition type...either in XP or with an old win98 boot disk (or I've sometimes been able to use a DR Dos disk where others haven't worked).

You might also try a fdisk /mbr to over-write the master boot record, just in case, and then partition the drive...

I think someone ran into a problem with one of my old hard drives when I had winNT 4.0 with NTFS, and they were trying to partition it under DOS and format as FAT. We tried several things of the sort to get around that (didn't have my NT 4 CD on me)... I finally cleared it with fdisk from DR Dos 7.03 as I remember...